Benign prostatic hyperplasia (BPH) is a common disorder in middle-aged and older men, with prevalence increasing with age. At age 70, more than one-half of men have symptomatic BPH, and nearly 90% of men have microscopic evidence of an enlarged prostate. The severity of symptoms also increase with age with 27% of patients in the 60-70 age bracket having moderate-to-severe symptoms, and 37% of patients in their 70's suffering from moderate-to-severe symptoms.
The prostate early in life is the size and shape of a walnut and weighs about 20 grams. Prostate enlargement appears to be a normal process. With age, the prostate gradually increases in size to twice or more its normal size. The fibromuscular tissue of the outer prostatic capsule restricts expansion after the gland reaches a certain size. Because of such restriction on expansion, the intracapsular tissue will compress against and constrict the prostatic urethra thus causing resistance to urine flow.
BPH is typically diagnosed when the patient seeks medical treatment complaining of bothersome urinary difficulties. The predominant symptoms of BPH are an increase in frequency and urgency of urination. BPH can also cause urinary retention in the bladder which in turn can lead to lower urinary tract infection (LUTI). In many cases, the LUTI then can ascend into the kidneys and cause chronic pyelonephritis, and can eventually lead to renal insufficiency. BPH also may lead to sexual dysfunction related to sleep disturbance or psychological anxiety caused by severe urinary difficulties. Thus, BPH can significantly alter the quality of life with aging of the male population.
BPH is the result of an imbalance between the continuous production and natural death (apoptosis) of the glandular cells of the prostate. The overproduction of such cells leads to increased prostate size, most significantly in the transitional zone which traverses the prostatic urethra.
In early stage cases of BPH, treatments can alleviate the symptoms. For example, alpha-blockers treat BPH by relaxing smooth muscle tissue found in the prostate and the bladder neck, which may allow urine to flow out of the bladder more easily. Such drugs can prove effective until the glandular elements cause overwhelming cell growth in the prostate.
More advanced stages of BPH, however, can only be treated by surgical or minimally invasive tissue ablation interventions. A number of methods have been developed using electrosurgical or mechanical extraction of tissue, and thermal ablation of intracapsular prostatic tissue. In many cases, such interventions provide only transient relief, and there often is significant peri-operative discomfort and morbidity.